There is a problem in achieving stability of a very soft ice cream packed in cups or bulk containers.
Inside the ice cream there are ice crystals and air bubbles dispersed in a liquid phase. Softness generally is obtained by reducing the quantity of ice formed and this is mainly obtained by selecting the type and the amount of sugars, by adding salt or alcohol in the ice cream mix. There is some limitation in the possibilities to play with the low molecular components mentioned above for taste reasons. Thus, if further increase of softness is targeted, the only possibility is to use polyols, e.g. glycerol which increases the risk of shrinkage. Shrinkage is a serious problem which makes the product unacceptable to the consumer: the volume of the ice cream shrinks, leaving a space either at the top or at the side of the package, which then appears unfull.
Unfortunately, the problem of instability raises with the volume of the liquid phase. Without willing to be bound by theory, when the volume of the liquid phase raises, the air bubbles have a tendency to go up which may lead to the formation of a layer of ice at the bottom of the container: this default is called layering.
In WO 01/06865 a solution to the problem of improved texture and stability of soft serve ice cream, in particular resistance to heat shock is obtained by creating fine and stable air cells with the aid of a specific blend of emulsifiers comprising propylene glycol monostearate, sorbitan tristearate and unsaturated monoglycerides.
EP-A-1 321 043 relates to a frozen aerated ice cream which has a soft structure at −18° C., contains high amounts of freezing point depressing sugars and contains less than 0.5% by weight glycerol. Since it is for use with soft serve ice dispensing devices which comprise extrusion of cartridges containing the soft ice cream on the place of consumption, shrinkage is not an issue since the consumer would not notice it.
The purpose of the invention is to achieve stabilization of soft serve ice cream type of product for home use with high resistance to shrinkage and layering.